Fluid parameter sensor and meter

ABSTRACT

An example fluid parameter sensor and meter is disclosed to measure at least one parameter of a fluid. In an example, the fluid parameter meter includes an outer conduit. A sensor element assembly is disposed in the outer conduit and has at least one straight uniform sensor element with an open interior to convey the fluid inside of the sensor element assembly. At least one mounting flexure is fixedly attached to the sensor element assembly and to the outer conduit. The at least one mounting flexure is configured to enable the sensor element assembly to vibrate in a natural radial mode shape of vibration. At least one vibration driver causes the sensor element assembly to vibrate. At least one vibration sensor senses the vibration of the sensor element assembly.

PRIORITY CLAIM AND CROSS REFERENCE

This application claims the priority benefit of U.S. Provisional PatentApplication No. 62/097,209 filed Dec. 29, 2014 for “A Vibrating ElementType Fluid Parameter Meter And Sensor For Abrasive Fluids” of Donald R.Cage, et al., incorporated by reference in its entirety as though fullyset forth herein.

BACKGROUND

Meters for measuring fluid parameters generally have not been successfulfor abrasive fluids (e.g., fluids common in the hydraulic fracturingindustry). These meters are often subject to premature failure and weardue to poor hydro-dynamic designs. Wear of the vibrating element alsoleads to a change in instrument calibration because the calibrationfactor is partly due to the geometry of the vibrating element, andabrasive wear changes the geometry. Traditional split-flow, and or benttube type flow meters, densitometers and viscometers are examples ofpoor hydro-dynamic designs that are subject to failure and wear andcalibration changes when used on abrasive fluids. Having a flow splitteror an elbow, or a bend or flange in the fluid path exacerbates wearcaused by abrasive fluids because the abrasive particles in the fluidtend to scrape the outside of a curved path due to centrifugal forces.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an isometric view of an example fluid parameter meter.

FIG. 1B is a cross section view looking down the central fluid flow axisof the example fluid parameter meter of FIG. 1A.

FIG. 1C is an oblique cross section view of the example fluid parametermeter of FIG. 1A.

FIG. 1D is a close up view of the example electromagnetic driver shownin FIG. 1C.

FIG. 2A is an isometric view of an example sensor element assembly.

FIG. 2B is a cross section view looking down the central fluid flow axisof the example sensor element assembly shown in FIG. 2A.

FIG. 2C and 2D are two views of an example sensor element assembly shownas finite element analysis deflected shapes due to radial modevibration.

FIG. 3A is an isometric view of another example sensor element assemblyhaving six mounting flexures at each end and six transducer magnets.

FIG. 3B and 3C are two views of an example sensor element assembly shownas finite element analysis deflected shapes due to radial modevibration.

FIG. 4A is an isometric view of another example sensor element assemblyhaving eight mounting flexures at each end and eight transducer magnets.

FIG. 4B and 4C are two views of an example sensor element assembly shownas finite element analysis deflected shapes due to radial modevibration.

FIG. 5A is an isometric view of another example fluid parameter meter,where the sensor element assembly has two sensor element conduitsarranged in parallel as a concentric pair.

FIG. 5B is a view down the central fluid flow axis of the example fluidparameter meter shown in FIG. 5A.

FIG. 5C and 5D are two views of an example sensor element assembly shownas finite element analysis deflected shapes due to radial modevibration.

FIG. 6A is an isometric view of another example fluid parameter meter,where the sensor element assembly has of a plurality of sensor elementconduits arranged in parallel clustered around a central sensor element.

FIG. 6B and 6C are two views of an example sensor element assembly shownas finite element analysis deflected shapes due to radial modevibration.

FIG. 7A through 7D show example sensor element shapes that arenon-circular.

FIG. 8 is an isometric view of another example sensor element assemblyhaving a pattern of openings or holes in sensor element.

FIG. 9A is an isometric view of an example sensor element assemblyhaving four mounting flexures arranged at the mid length position of thesensor element, and having hydro-dynamically shaped magnet guards toprotect the magnets.

FIG. 9B and 9C are two views of an example sensor element assembly shownas finite element analysis deflected shapes due to radial modevibration.

FIG. 10 is a close up cross section view of an example sensor elementhaving a pattern where the openings are specifically shaped to inducefluid flow there through.

FIG. 11 is an example wear guard configured to protect the leading edgesof a sensor element assembly from abrasive wear.

FIG. 12 is an oblique view of an example sensor element assembly andwear guard shown in alignment for protecting the sensor element assemblyfrom abrasive wear.

FIG. 13 is a graph illustrating a relationship between vibration periodsquared versus fluid specific gravity for an example fluid parametermeter, to determine fluid density from vibration period.

FIG. 14 is a block diagram showing signal processing for an examplefluid parameter meter.

FIG. 15A is an isometric view of an example sensor element assembly,where the mounting flexures are arranged tangent to the sensor elementand are attached to the sensor element on anti-nodal areas.

FIG. 15B and 15C are two views of the example sensor element assembly ofFIG. 15A shown as Finite Element deflected shapes from a selected modeof vibration.

FIG. 16A is an isometric view of another example fluid parameter meter,where the sensor element assembly has sets of transducer magnetsarranged near both ends of sensor element to facilitate multiple modesof vibration and mode shapes that invert along the length of the sensorelement.

FIG. 16B and 16C are two views of the example sensor element assemblyshown as Finite Element Analysis deflected shapes from a selected modeof vibration.

FIG. 16D and 16E are two views of the example sensor element assemblyshown as Finite Element Analysis deflected shapes from a selected modeof vibration, where the radial mode shape inverts along the length ofthe sensor element.

FIG. 17 is a block diagram showing signal processing for an examplefluid parameter meter, where fluid flow rate is determined along withother fluid parameters.

FIG. 18A is an isometric view of an example sensor element assembly,where the mounting flexures are arranged tangent to the sensor elementand are attached to the sensor element on nodal areas.

FIG. 18B and 18C are two views of the example sensor element assembly ofFIG. 18A, shown as Finite Element deflected shapes from a selected modeof vibration.

DETAILED DESCRIPTION

In the hydraulic fracturing industry, measurement of PPA (“Pounds ofPropant Added”) is important, and often employs nuclear densitometershaving a radioactive source. However, these types of meters create aradiation exposure hazard to those nearby, and a national security riskshould the equipment ever be lost or stolen. The United States NuclearRegulatory Commission (“NRC”) heavily regulates these devices because ofthe radioactive sources. Requisite reporting and security measuresgreatly increases the cost of ownership.

A fluid parameter meter is disclosed herein which may be employed, forexample, in the hydraulic fracturing industry to eliminate the costs andconcerns associated with current measurement devices. In an example, thefluid parameter meter includes a vibrating element type fluid parametermeter capable of measuring abrasive fluid parameters including fluidflow rate, fluid density, viscosity, temperature, and other parametersthat can be calculated therefrom such as Reynolds Number, kinematicviscosity, mass flow rate, volume flow rate, net oil percentage, Gasvolume fraction (“GVF”), and pounds of propant added (“PPA”), massconcentration, volume concentration, and others. The vibrating elementis one or more uniform conduits fully immersed in the fluid to bemeasured and hydro-dynamically configured to minimize obstruction to theflow and to wear due to abrasive fluids such as hydraulic- fracturing(“fracking”) fluids, oil well cementing fluids, slurries, and the like.Remote electromagnetic drivers and sensors are employed to cause anddetect the requisite vibration from outside the fluid boundary, therebyallowing the vibrating element to freely vibrate without encumbrance. Byisolating the vibrating element from the pressure and stress effects onthe fluid boundary pipe, higher accuracy is achieved in a simple,robust, and wear resistant configuration.

In an example, the fluid parameter meter has a vibrating sensor elementassembly comprised of one or more sensor elements, each having the shapeof a straight uniform conduit, mounted within a straight section ofouter conduit which bears the fluid pressure and pipeline stresses andvibrations. Each sensor element is a straight conduit, having a uniformand relatively small cross sectional area perpendicular to fluid flowdirection, and having a central axis parallel to the fluid flowdirection. One or more sensor element may be configured to vibrate inone or more natural radial type modes of vibration.

Radial modes of vibration have shapes that involve node areas havingminimal vibration amplitude, and antinode areas having maximum vibrationamplitude. In an example, attachment of the sensor element assembly intoan outer conduit is accomplished with light springs (mounting flexures)attached at selected node or antinode areas, so that they do notsubstantially interfere with, or alter the natural radial mode shape ofvibration that the sensor element assembly has vibrating freely byitself. These mounting flexures are also configured not to interferewith the fluid flow by minimizing their cross sectional areaperpendicular to the fluid flow direction.

During operation, the sensor element assembly vibrates byelectromagnetic transducers in one or more of its natural radial modesof vibration, at a prescribed amplitude and frequency, which inducesfluid acceleration levels in the range of ten “g's” or less, and in anexample, less than one “g”.

In an example, the sensor element is a relatively thin walled roundmetal tube and is about one or two diameters long (although it may bemore or less than this). The mounting flexures are metal fins having theapproximate thickness of the wall of the sensor element. The mountingflexures connect between the outer conduit and the sensor element alongthe sensor element's vibrational node areas where vibration amplitudesare minimal.

By selecting thin walled sensor elements and mounting flexures relativeto the diameter of the outer conduit, the flow area of the outer conduitmay be ten to fifty times greater than the obstructed area of the sensorelement and mounting flexures combined. With only about 2% to 10% of theflow area obstructed by sensor elements and mounting flexures, themeasured fluids flow through the meter with little or no obstruction andpressure loss and wear. In addition, vibrating the fluid at accelerationlevels (e.g., around ten “g's” or less, and in an example, less than one“g”), eliminates or minimizes induced cavitation and particle slippageinduced wear.

In an example, the sensor element assembly is configured with aplurality of individual sensor element conduits arranged in parallel orseries. As such, sensitivity to velocity profile effects can beminimized. An example is described herein with two uniform sensorelement conduits of different diameters and arranged in parallel as aconcentric pair. Another example is described herein having a pluralityof smaller sensor element conduits arranged in parallel around a largercentral sensor element. Still other examples are contemplated, as willbe apparent to those having ordinary skill in the art after becomingfamiliar with the teachings herein.

Abrasive fluids flowing through the meter generally flow parallel to thevibrating walls of the sensor element and directly impinge on theleading edges of the sensor element and mounting flexures. The sensorelements and mounting flexures can therefore be protected from wear bymanufacture of abrasion resistant materials (e.g., abrasion resistant orhardened steel, or ceramic, or polymer). In addition, the leading edgescan be further protected by hardening, or by coating, or by a wear guardmounted upstream from the sensor element assembly.

Several sensor element examples are described herein having variouscross sectional shapes and various arrangements of mounting flexures anddrive and sense magnets to enable vibration of various natural modes ofvibration. In addition, example sensor elements are described hereinhaving patterns of openings holes or slots to enable fluid flow throughthe wall of the sensor element to modify meter measurement sensitivity,minimize wall effects, and minimize power consumption. Also describedare openings or holes in the sensor element that are specifically shapedto induce flow between the sensor element interior and exteriorsurfaces.

The fluid parameter meter disclosed herein can be provided as a sensor,or as a complete meter or system, because the sensors are oftenmanufactured and sold separately from controlling electronics orcomplete meters. Therefore, the description of the fluid parameter meterherein is not limited in application, and applies to both sensors andmeters or systems.

Before continuing, it is noted that as used herein, a complete “meter”may be referred to as a combination of a “sensor” and its controlling“electronics.” The sensor may be defined as the mechanical portion of ameter including, but not limited to, a flow conduit pipe, sensor elementtubes, magnets, coils, armatures, temperature sensors, mountingflexures, flanges and the like. The electronics may be defined as thatportion of a complete meter that receives and sends electrical signalsto the sensor, and processes those signals for various control andparameter determinations.

It is also noted that the terms “hole” or “holes” and “opening” or“openings” are used interchangeably herein.

In addition, the terms “includes” and “including” mean, but is notlimited to, “includes” or “including” and “includes at least” or“including at least.” The term “based on” means “based on” and “based atleast in part on.”

FIG. 1A is an isometric view of an example fluid parameter meter 100.FIG. 1B is a cross section view looking down the central fluid flow axisof the example fluid parameter meter 100 of FIG. 1A. FIG. 1C is anoblique cross section view of the example fluid parameter meter 100 ofFIG. 1A. FIG. 1D is a close up view of the example electromagneticdriver shown in FIG. 1C. FIG. 2A is an isometric view of an examplesensor element assembly 200. FIG. 2B is a cross section view lookingdown the central fluid flow axis of the example sensor element assembly200 shown in FIG. 2A. FIG. 2C and 2D are two views of an example sensorelement assembly 200 shown as finite element analysis deflected shapesdue to radial mode vibration.

An example fluid parameter meter 100 includes flanges 103 and 104 which,and for this example are standard 6 inch 150 pound ANSI pipe flanges.Flanges 103 and 104 are welded to outer conduit 102 which is a 6 inchpipe. Also mounted in association with the outside of outer conduit 102is electronics housing 108 which holds the control electronics 1401through 1405 for meter 100. Also mounted in association with outerconduit 102 are magnet-coil assemblies 105A and 105B, and 106A and 106B,and wire conduits 107 for conveying electrical wires.

In an example, a temperature sensor 113 is mounted in association withouter conduit 102. The temperature sensor may be a platinum RTD(resistive thermal device) in a thermal well arrangement for determiningfluid temperature in a pipe. Temperature sensor 113 is configured toacquire an accurate temperature of any fluid inside of outer conduit102. In an example, temperature sensor 113 may be provided for reportingfluid temperature to the meter user, and for compensating fortemperature related material property changes in sensor element assembly200.

In an example, sensor element assembly 200 is mounted inside of outerconduit 102, as shown in detail in FIG. 2A and 2D. Sensor elementassembly 200 is comprised of sensor element 201 which is a round steeltube of 4 inch diameter, 0.06 inch wall thickness, and 6 inches long.Mounting flexures 202 through 205 are also made of steel in the shape ofthin walled flexural fins approximately 0.5 inches by 0.6 inches by 0.06inches thick, and are mounted by brazing or welding toward the lowerright (proximal) end of sensor element 201 of FIG. 2A, and along thesides of sensor element 201 on minimum vibration nodes. Mountingflexures 202 through 205 are aligned at 45, 135, 225, and 315 degreesrespectively, around the circumference of sensor element 201. Toward theopposite (distal) end of sensor element 201 are mounting flexures 206through 209 (not all mounting flexures are visible in all views) whichare similar to and aligned with mounting flexures 202 through 205respectively.

In an example, the sensor element assembly 200 has four permanentmagnets 210 through 213, fixedly attached to the side of sensor element201 about half way along its length, and at the peak displacementlocations (antinodes) for the mode of vibration (not all magnets arevisible in all views). By way of illustration, magnets 210 through 213may be samarium cobalt type magnets due to their strength andtemperature stability. In another example, neodymium iron, alnico, orother magnetic materials may be provided. Still other magnets may beprovided. Permanent magnets 210 through 213 are aligned at 0, 90, 180and 270 degrees respectively, around the circumference of sensor element201. Permanent magnets 210 through 213 can be interchangeably providedfor either causing requisite vibration, or for sensing the vibrationthus caused as further explained hereinafter.

In an example, sensor element 201 is a short straight section ofrelatively thin walled uniform tubing made of metal such as a corrosionresistant 300 series stainless steel, or a hardened type of metal suchas 410 stainless steel, or PH 17-4, or 4340 steel. Non-metals can alsobe provided for this purpose such as ceramics, plastics, reinforcedpolymers, reinforced polyphenylene-sulfide, glass filled nylon, and thelike. The length of sensor element 201 may be selected depending ondesired vibration characteristics. In an example, the length isgenerally about one or two diameters in length or shorter, and circularin cross sectional shape. FIG. 7A through 7D show alternate crosssectional shapes for sensor elements including octagonal 701, hexagonal702, multi-lobed shaped 703, or elliptical 704. In an example, outerconduit 102 may be a round stainless steel pipe, although other shapesmay also be implemented.

FIG. 1D shows a close up cross section view of magnet-coil assembly105A. Magnet-coil assembly 105A is comprised of permanent magnet 210which is fixedly attached to and moves with the vibration of sensorelement 201, and is protected from abrasive fluids by magnet guard 114which may be made of a hard abrasive resistant material such as 410,440, or 17-4 type stainless steel. Magnet guard 114 can be a simpletubular sleeve, but may also be a more hydrodynamic configuration asshown, and such as magnet guard 906 of FIG. 9A. Permanent magnet 210causes magnetic field 115 to emanate therefrom, and pass through thewall of outer conduit 102, through armature 116, and through electricalcoil 117. Electrical coil 117 is held in place by an interconnectingprinted circuit board 118 and by fastener 119. In an example, armature116 enhances the magnitude and direction of magnetic field 115, forexample, if it is made of a magnetically permeable material such ascarbon steel or 400-series stainless steel or the like.

In an example, magnet coil assemblies 105A, 105B, 106A, and 106B are allconstructed in the same way as just described for magnet coil assembly105A, therefore each magnet coil assembly can be provided either as avibration driver or as a vibration sensor and are thereforeinterchangeable. As the mode of vibration for this example causeselliptical deflections of the sensor element 201 cross sectional shapeas shown in FIG. 2C and 2D, diametrically opposite magnet coilassemblies can be electrically connected together to work as a pair.Thus, magnet coil assemblies 105A and 105B are electrically connectedand work as one vibration sensor as shown in electrical schematic 1400of FIG. 14 where electrical signals from magnet coil pair 105A and 105Bsupply a vibration related signal to amplifier 1401. Similarly, magnetcoil assemblies 106A and 1066 can be electrically connected as a pairand work as one vibration driver as shown in FIG. 14 where amplifier1402 supplies electrical excitation to magnet coil assemblies 106A and106B.

FIG. 14 also shows control module 1404 which receives vibration signalsfrom amplifier 1401, and thereby controls amplifier 1402 to supply therequisite vibration forces to maintain a prescribed vibration mode andamplitude. Temperature Sensor 113 is also represented in electricalschematic 1400 and is also connected to control module 1404 viaamplifier 1403 to deliver fluid temperature related signals thereto.

During operation, control module 1404 uses vibration signals andtemperature signals to determine output fluid parameters 1405 such asfluid density, viscosity, temperature, and other calculated results suchas net percentage oil, pounds of propant added, gas volume fraction, orothers. The determination of these calculated results may also involveuser input or assumed values such as water density, propant density, orothers.

An example method of vibrating the sensor element assembly is nowbriefly described. Ambient vibration on sensor element assembly 200causes an electrical signal in magnet coil assemblies 105A and 105Bwhich is amplified by amplifier 1401 and passed along to control module1404. Control module 1404 creates an output signal related to thevibration that is detected by magnet coil assemblies 105A and 105B. Thisoutput signal, usually a sine wave, is amplified by amplifier 1402 andconverted to a current of the appropriate phase and amplitude toreinforce the vibration just detected. The current thus created passesthrough magnet coil assemblies 106A and 106B thereby causing forces onsensor element assembly 200 to reinforce the desired vibration shape214. By reinforcing the detected vibration in this way, the amplitude ofthe vibration shape 214 on sensor element assembly 200 may increaseuntil it reaches a specified amplitude as determined by control module1404. Once the specified amplitude is achieved, the amplification fromamplifier 1402 is reduced to a level to maintain the specified vibrationshape 214 amplitude. This vibration amplitude is maintained duringnormal operation and while the desired fluid parameters are determined.

To determine fluid density in an example, the period of oscillation isdetermined and squared by control module 1404. The period squared valueis a representation of fluid density or specific gravity. FIG. 13 isgraph 1300 of four different fluid specific gravities, plotted againsttheir vibration period squared value. Graph 1300 shows a general linearrelationship between vibration period squared and fluid specificgravity. This graph 1300 can therefore be reduced to an equation forcontrol module 1404 to calculate any fluid's specific gravity based onthe vibration period. Normally each meter is calibrated at the factoryto determine the equation of graph 1300 by testing the meter on two ormore fluids such as air and water. The equation to calculate fluiddensity based on vibration period can also involve compensation valuesbased on temperature and viscosity or others.

To determine fluid viscosity in an example, the power or force tomaintain a prescribed level, or velocity, or amplitude of vibration isdetermined by control module 1404 as a representation of fluidviscosity. As an example, the force to cause sensor element vibration,divided by the velocity of the resulting vibration is proportionallyrelated to fluid damping or viscosity.

To determine temperature in an example, the RTD 113 is normally aplatinum type thin film or wire wound type sensor and circuit module1403 is a commercial integrated circuit that supplies RTD 113 with asmall current and measures the resistance of the RTD and converts thatresistance to a temperature signal which is supplied to control module1404. This is accomplished by application of the Callender Van Dusenequation and there are many commercially available electronic modulesavailable for this purpose.

To determine the calculated result of PPA (“pounds of propant added”) inan example, the fluid density is determined by the method earlierdescribed. Using a user supplied density of the propant, and a usersupplied or assumed density of the fluid mixed with the propant, the PPAcan thereby be determined as a function of the two known densities, andthe measured density of the mixed fluid in the meter.

Similarly, the percentage of oil in a mixture of water and oil “net oil”can be determined. Providing a user specified or an assumed density forthe water portion of the mixture, the net-oil percentage can bedetermined in an example, as a function of the measured density of themixture, and the user specified or assumed density of the water.

Similarly, gas volume fraction (“GVF”) of a mixture of gas and fluid canbe determined. Using a user specified or an assumed density for thefluid portion of the mixture, the GVF can be determined in an example,as a function of the measured density of the mixture, and the userspecified or assumed density of the fluid.

Following is an example for a sensor element assembly 200 along withdensity test results. In this example, Sensor Element 201 is 6″ long, 4″diameter, 0.06″ wall thickness, 316 SS. The Mounting Flexures are202-209: 0.5″ wide, 0.6″ tall, 0.06″ thick, 316 SS. The Magnets are210-213: 0.5″ diameter 0.5″ long, Samarium Cobalt. Density Results areplotted in FIG. 13, line 1300 and show a linear relationship betweenfluid specific gravity (SG) and vibration period squared (VP̂2). Testresults are shown in Table 1.

Fluid SG Frequency (Hz) VP 

 2 Air 0.001 465 4.62e−6 Water 1.00 226 1.96e−5 Fracking Fluid 1.4 196 2.6e−5 Zinc Bromide 2.2 160  3.9e−5

In an example, the amplitude of vibration shape 215 to accurately detectand drive the vibration frequency on water can be 0.0002″ or less.Acceleration equals amplitude times circular frequency squared.Therefore, the acceleration level for this example on water is given bythe following equation:

Acceleration=0.0002*(2*pi*226)̂2=403 in/sec/sec  EQ 1

The result is slightly more than one “g” of acceleration. This lowacceleration level eliminates or minimizes induced cavitation andparticle slippage problems.

Before continuing, it should be noted that the examples described aboveare provided for purposes of illustration, and are not intended to belimiting. Other devices and/or device configurations may be utilized tocarry out the operations described herein.

FIG. 3A is an isometric view of another example sensor element assembly300 having six mounting flexures at each end and six transducer magnets.FIG. 3B and 3C are two views of an example sensor element assembly 300shown as finite element analysis deflected shapes due to radial modevibration.

FIG. 3A is another example sensor element assembly 300. Sensor elementassembly 300 is similar to sensor element assembly 200 except thatinstead of having 4 mounting flexures at each end of the sensor elementassembly 200, sensor element assembly 300 has six mounting flexures 302and 303 at each end, and 6 magnets 304 at the mid length position.Having six mounting flexures at each end 302 and 303, and six magnets304 allows sensor element assembly 300 to vibrate in a higher order modeof vibration where the cross section vibration shape 305 is moretriangular as shown in FIG. 3B and 3C. In an example, the vibrationshape 305 is uniform along the length of sensor element assembly 300.

The operation of sensor element assembly 300 is similar to that ofsensor element assembly 200 earlier described, except that six magnets304 are provided for driving and sensing the vibration motion 305, threefor driving and three for sensing the vibration motion 305. In thisexample, three magnets 304 are provided for driving and three magnets304 are provided for sensing so that the driving forces are balanced. Itis noted however, that other combinations of driving and sensing magnetsmay be provided.

FIG. 4A is an isometric view of another example sensor element assembly400 having eight mounting flexures at each end and eight transducermagnets. FIG. 4B and 4C are two views of an example sensor elementassembly 400 shown as finite element analysis deflected shapes due toradial mode vibration.

FIG. 4A is another example sensor element assembly 400. Sensor elementassembly 400 is similar to sensor element assembly 300, except thatinstead of having six mounting flexures at each end of the sensorelement assembly 300. Sensor element assembly 400 has eight mountingflexures 402 and 403 at each end, and 8 magnets 404 at the mid lengthposition. Having eight mounting flexures 402 and 403, and eight magnets404 allows sensor element assembly 400 to vibrate in a higher mode ofvibration where the cross section vibration shape 405 is morerectangular as shown in FIG. 4B and 4C. In an example, the vibrationshape 405 is uniform along the length of sensor element assembly 300.

The operation of sensor element assembly 400 is similar to that ofsensor element assembly 200 earlier described, except that eight magnets404 are provided for driving and sensing the vibration motion 405, fourfor driving and four for sensing the vibration motion 405. In thisexample, four magnets 404 are provided for driving and four magnets 404are provided for sensing so that the driving forces are balanced. It isnoted, however, that other combinations of driving and sensing magnetsmay be provided.

FIG. 5A is an isometric view of another example fluid parameter meter,where the sensor element assembly 500 has two sensor element conduitsarranged in parallel as a concentric pair. FIG. 5B is a view down thecentral fluid flow axis of the example fluid parameter meter shown inFIG. 5A. FIG. 5C and 5D are two views of an example sensor elementassembly 500 shown as finite element analysis deflected shapes due toradial mode vibration.

In FIG. 5A, the fluid parameter meter has two concentric sensor elements501 and 502 which are round straight metal conduits. Outer sensorelement 501 has four mounting flexures 503 through 506 fixedly attachedto the near (proximal) end and four mounting flexures 507 through 510(507 not visible in this view) fixedly attached to the far (distal) end.Mounting flexures 503 through 510 may also be fixedly attached to theinside of an outer conduit 519. Magnets 521 through 524 are also fixedlyattached to the outer sensor element 501 at its mid length position, andcircumferentially rotated by 45 degrees from the mounting flexures 503through 510 so that they coincide with vibration antinodes.

In an example, inner sensor element 502 is fixedly attached to mountingflexures 511 through 518 which are in circumferential alignment withmagnets 521 through 524 so that they coincide with vibration antinodesof outer sensor element 501.

Sensor element assembly 500 can be substituted for sensor elementassembly 200 as earlier described, and operated in the same way. Anadvantage of having two concentric sensor elements 501 and 502 connectedby mounting flexures 511 through 518 is that both sensor elements 501and 502 vibrate in unison 525 as shown in FIG. 5C and 5D. Thisconcentric arrangement minimizes velocity profile effects because moreof the fluid is vibrated at the amplitude of the sensor elements,especially in the annular space between the sensor elements 501 and 502.

FIG. 6A is an isometric view of another example fluid parameter meter,where the sensor element assembly 600 has of a plurality of sensorelement conduits arranged in parallel clustered around a central sensorelement. In FIG. 6A, a plurality of smaller sensor elements 603 arearranged around a central sensor element 601. As before, mountingflexures 602 may be fixedly attached to an outer conduit (not shown). Nomagnets are shown on this example for visual clarity but may be providedas described on earlier examples.

FIG. 6B and 6C are two views of an example sensor element assembly 600shown as finite element analysis deflected shapes due to radial modevibration. An advantage to sensor element assembly 600 is that itreduces velocity profile effects because the smaller sensor elements 603capture and vibrate the fluid at the same vibration amplitude 620 as thesensor element 601 thereby vibrating more of the fluid than may bevibrated by sensor element 601 alone.

In operation, sensor element assembly 600 may have 4 magnets attached atthe mid length position (not shown) at the antinodes of vibration 620,and may be operated as earlier described for sensor element assembly200.

FIG. 7A through 7D show example sensor element shapes that arenon-circular. FIG. 7A shows an example of an octagonal sensor element701. FIG. 7B shows an example of a hexagonal sensor element 702. FIG. 7Cshows an example of a four-lobed clover leaf shaped sensor element 703.FIG. 7D shows an example of an oval or elliptical shaped sensor element704. Any of the shapes of sensor elements 701 through 704 and others canbe used.

FIG. 8 is an isometric view of another example sensor element assembly800 having a pattern of openings or holes in sensor element. In thisexample, the sensor element assembly 800 includes sensor element 801,which is a round straight section of metal conduit. Sensor element 801includes hole pattern 802 allowing fluid to flow between the inside andthe outside of sensor element 801. Sensor element 801 also includesmounting flexures 803 through 810 which are metal fins of the sameapproximate thickness as is sensor element 801 and are arranged in thesame manner and fixedly attached in the same manner as earlier describedfor sensor element assembly 200. No magnets are shown for visualclarity, but may be provided as in earlier examples.

An advantage of having hole pattern 802 in sensor element 801 is that itallows fluid flow between the inside and the outside of sensor element801 and thereby reduces wall effects. As the annular space between asensor element and an outer conduit becomes smaller, fluid becomes moretrapped there between. This entrapment of fluid inhibits the fluid'sability to move and accelerate under the influence of a vibrating sensorelement. This inhibiting effect changes the vibrational frequency anddamping characteristics of the sensor element assembly, and also changesthe meters sensitivity to measuring fluid density and viscosity. Makingthe annular space large is sometimes not practical due to spaceconstraints in a particular configuration, therefore by adding holepattern 802, the vibration inhibiting affect is minimized or eliminated.

FIG. 9A is an isometric view of an example sensor element assembly 900having four mounting flexures arranged at the mid length position of thesensor element, and having hydro-dynamically shaped magnet guards toprotect the magnets. Sensor element assembly 900 is shown includingsensor element 901, which is a round straight tubular sensor elementmade of metal and includes four mounting flexures 902 through 905 (902not visible in this view). Mounting flexures 902 through 905 are locatedat the mid length position of sensor element 901 and are mounted alongits node areas where vibration amplitude is minimal. Magnet assemblies906 through 909 (908 is not visible in this view) are configured havinghydro-dynamically shaped magnet guards to protect them from abrasion.Magnet assemblies 906 through 909 are circumferentially rotated 45degrees from the mounting flexures 902 through 905 so that they arelocated in anti-node areas of maximum deflection. In operation, sensorelement assembly may be operated in the same way as was earlierdescribed for sensor element assembly 200.

FIG. 9B and 9C are two views of an example sensor element 900 assemblyshown as finite element analysis deflected shapes due to radial modevibration. FIG. 9B and 9C show a finite element analysis plot of how thevibration shape 920 of sensor element assembly 900 is elliptical anduniform along its length.

FIG. 10 is a close up cross section view of an example sensor element1000 having a pattern where the openings are specifically shaped toinduce fluid flow there through. Sensor element 1000 includes holepattern 1001 where the holes are specifically shaped in such a way toinduce fluid flow 1004 to pass through from the outside in through hole1002 and from the inside out through hole 1003 as shown in FIG. 10. Thisexample configuration can decrease wall effects and particle slippageand velocity profile effects, especially in low viscosity fluids becauseit induces more particle-tube interaction. The shape of the holes inhole pattern 1001 can be angled as shown in FIG. 10 by laser cutting, orpunching, or machining, or other forming methods.

FIG. 11 is an example wear guard 1100 configured to protect the leadingedges of a sensor element assembly from abrasive wear. Abrasive wear wasearlier described as most severe on the leading edges of the sensorelement and on the mounting flexures. Therefore, an example wear guard1100 is shown having the same cross sectional shape perpendicular to thedirection of fluid flow as does the sensor element assembly it is toguard. Wear guard 1100 is therefore comprised of guard element 1101, andguard mounting supports 1102 through 1105 all of which have a similarsize and shape as a sensor element assembly it is configured to guard.When mounted upstream from a sensor element assembly, the wear guard1100 takes the brunt of the direct impingement of the abrasive wear andprotects the leading edges of any sensor element assembly locateddownstream.

FIG. 12 is an oblique view of an example sensor element assembly andwear guard 1100 shown in alignment for protecting the sensor elementassembly from abrasive wear. FIG. 12 shows the just described assemblyof wear guard 1100 and sensor element assembly 200. Sensor element 201is coaxially aligned with guard element 1101 and spaced apart to leave agap 1201 there between. By using wear guard 1100 upstream from sensorelement assembly 200, direct impingement of abrasive particles on theleading edges of sensor element assembly 200 is avoided, and wear istherefore minimized.

FIG. 13 is a graph illustrating a relationship between vibration periodsquared versus fluid specific gravity for an example fluid parametermeter, to determine fluid density from vibration period. The valuesgiven in Table 1 described previously are plotted along curve 1300showing the generally linear relationship between vibration periodsquared, and fluid specific gravity SG as was earlier described.

FIG. 14 is a block diagram showing signal processing for an examplefluid parameter meter. The function of signal processing block diagram1400 was earlier described with reference to fluid parameter meter 100.Signal processing diagram 1400 is representative of many of the sensorembodiments previously described and can be used with any of them withsome variations for having more driving and sensing transducers for someof the examples shown.

FIG. 15A is an isometric view of an example sensor element assembly1500, where the mounting flexures are arranged tangent to the sensorelement and are attached to the sensor element on anti-nodal areas.Example sensor element assembly 1500 includes sensor element 1501, andmounting flexures 1502 through 1509 (1509 is not visible in this view)are mounted generally tangent to the surface of sensor element 1501 onthe anti-node areas; rather than being mounted radially in node areas aswas the case for the previous examples. Mounting flexures 1502 through1509 have a thickness perpendicular to the direction of fluid flowsimilar to sensor element 1501 to minimize obstruction to flow. Mountingflexures 1502 through 1509 also include bends to facilitate mounting andto facilitate a specified stiffness.

An advantage of arranging the mounting flexures 1502 through 1509tangentially as shown, is that the natural modes of vibration can beless influenced by the stiffness of the mounting flexures, and thestress in the mounting flexures 1502 through 1509 can be configured tohave lower values because they can be made to be any length regardlessof the width of the annular space between the sensor element 1501 andthe outer conduit in which it may be mounted (not shown). Magnets 1510through 1513 (magnets 1512 and 1513 not visible in this view) arehydro-dynamically shaped to prevent abrasive wear.

FIG. 15B and 15C are two views of the example sensor element assembly ofFIG. 15A shown as Finite Element deflected shapes from a selected modeof vibration. FIG. 15B and 15C are finite element analysis deflectedshape predictions for an example mode of vibration of sensor elementassembly 1500 and show the vibration deflected shape 1514. Sensorelement assembly 1500 can be provided as a direct replacement for sensorelement assembly 200 and functions in the same way as previouslydescribed.

FIG. 16A is an isometric view of another example fluid parameter meter,where the sensor element assembly has sets of transducer magnetsarranged near both ends of sensor element to facilitate multiple modesof vibration and mode shapes that invert along the length of the sensorelement. FIG. 16B and 16C are two views of the example sensor elementassembly shown as Finite Element Analysis deflected shapes from aselected mode of vibration. FIG. 16D and 16E are two views of theexample sensor element assembly shown as Finite Element Analysisdeflected shapes from a selected mode of vibration, where the radialmode shape inverts along the length of the sensor element.

FIG. 16A shows another example where a set of four magnets 1610 through1613 are arranged near the lower right proximal end of sensor element1601, and another set of four magnets 1614 through 1617 are arrangednear the upper left distal end of sensor element 1601. This arrangementallows for modes of vibration that invert in shape along the length ofsensor element 1601, as well as modes that do not invert along thelength of sensor element 1601. Each magnet 1610 through 1617 isaccompanied by a corresponding coil not shown (for visual clarity) inFIG. 16A through 16E (but shown in FIG. 17 as having the same magnetnumber and an “A” designation thereafter). Coils 1610A and 1612A arewired together to act as one coil to sense radial mode shape vibrationat the proximal end of sensor element 1601. Coils 1614A and 1616A arewired together to act as one coil to sense radial mode shape vibrationat the distal end of sensor element 1601.

FIG. 16B and 16C are finite element deflected shape predictions ofsensor element assembly 1600 where the selected mode shape motion 1618is elliptical in cross section shape and is uniform along the length ofsensor element 1601. FIG. 16D and 16E are finite element deflected shapepredictions of sensor element assembly 1600 where the selected modeshape motion 1619 is elliptical in cross section shape and is notuniform along the length of sensor element 1601, but instead thedeflection shape 1619 inverts once from the distal end to the proximalend of sensor element 1601. This mode shape can causes Coriolis forcesalong the length of sensor element 1601 which in turn cause Coriolisdeflections similar to deflected shape 1618. This feature measures fluidflow rate using the Coriolis effect as next described.

FIG. 17 is a block diagram showing signal processing for an examplefluid parameter meter, where fluid flow rate is determined along withother fluid parameters. Temperature sensor 1713 is shown in FIG. 17 butnot in FIG. 16A through 16E for visual clarity. Temperature sensor 1713along with amplifier 1703 measures the temperature of the fluid flowingin and around sensor element assembly 1600 and relays that signal tocontrol module 1704 for thermal affect compensation and for reporting asa temperature output signal 1705.

The circuit shown in FIG. 17 may be provided in conjunction with sensorelement assembly 1600. To cause Coriolis forces along the sensor element1601, vibration shape 1619 is induced to vibrate by amplifier 1702driving magnet coil pairs 1611(A) and 1613(A) together in phase witheach other, but out of phase by 180° from driving magnet coil pairs1615(A) and 1617(A).

In an example, to sense the driven vibration of motion shape 1619,signals from magnet coil pairs 1610(A) and 1612(A) are sensed byamplifier 1701 representing the radial motion at the proximal end ofsensor element 1601. Similarly, signals from magnet coil pairs 1614(A)and 1616(A) are sensed by amplifier 1701 representing the radial motionat the distal end of sensor element 1601. These signals are received bycontrol module 1704 to provide both drive control signals back todriving amplifier 1702 for drive control, and to determine fluidparameters such as fluid density, viscosity, temperature, flow rate, andother calculated results such as PPA, GVF, Net-oil, and others.

In an example, to determine fluid flow rate, Control module 1704calculates the phase or time difference between the distal end motionand the proximal end motion of sensor element 1601. This phasedifference can be proportionally related to the flow rate of fluidpassing through sensor element assembly 1600.

In an example, to determine the fluid parameters of density, viscosity,temperature, and other calculated results, the same methods may beapplied that were previously discussed for the example of FIG. 1. Inanother example, the calculated result of Reynolds Number may bedetermined as being a function of the measured parameters of flow ratevelocity, density and viscosity, and the pipe diameter, which are allknown or measured by the meter. In another example the calculated resultof kinematic viscosity can be calculated from the absolute, sometimescalled the (dynamic) viscosity and the fluid density which is measuredby the meter.

FIG. 18A is an isometric view of an example sensor element assembly1800, where the mounting flexures are arranged tangent to the sensorelement and are attached to the sensor element on nodal areas. FIG. 18Band 18C are two views of the example sensor element assembly of FIG.18A, shown as Finite Element deflected shapes from a selected mode ofvibration.

The example sensor element assembly 1800 includes sensor element 1801,and mounting flexures 1802 through 1809 are mounted generally tangent tothe surface of sensor element 1801 along their mid-spans, and on thenodal areas of sensor element 1801 for selected modes of vibration.Mounting flexures 1802 through 1809 have a thickness perpendicular tothe direction of fluid flow similar to sensor element 1801 to minimizeobstruction to flow. Mounting flexures 1802 through 1809 can includebends to facilitate mounting and to facilitate a specified stiffness.Mounting flexures 1802 through 1809 are fixedly attached to mountingblocks 1814 through 1821 (mounting block 1821 not visible in this view)at their distal ends.

In an example, mounting blocks 1814 through 1824 are configured to allowmounting the entire sensor assembly 1800 to the outer conduit (not shownin this view). Mounting blocks 1814 through 1824 can be fixedly attachedto an outer conduit by any means including brazing, welding, adhesion,or by bolting through holes as is shown in this example.

An advantage of arranging the mounting flexures 1802 through 1809 asshown, is that the natural modes of vibration can be less influenced bythe properties of the mounting flexures, and the stress in the mountingflexures 1802 through 1809 can be configured to have specific or lowervalues because they can be made to be any stiffness regardless of thewidth of the annular space between the sensor element 1801 and the outerconduit in which it may be mounted (not shown).

Instead of the magnets in previous examples for driving and sensing thevibration of sensor assembly 1801, in this example, armatures 1810through 1813 (armatures 1812 and 1813 not visible in this view)magnetically couple sensor assembly 1801 to driving and sensingelectro-magnetic coils (not shown in this view) outside of an outerconduit.

Armatures 1810 through 1813 may be made of magnetically permeablematerial such as carbon steel, type 410 stainless steel, type 430stainless steel, Carpenter Steel Corporation High Permeability Alloy 49,HyMu 80 alloy, transformer iron, silicon iron, ferrite, and the like.Armatures 1810 through 1813 may be fixedly attached to sensor element1801 by any method including brazing, welding, adhesion, fusion bonding,and the like.

If the material of sensor element 1801 is magnetically permeable, thenarmatures 1810 through 1813 may not be provided because the wall ofsensor element 1801 can function as an armature thereby magneticallycoupling with driving and sensing coils outside of an outer conduit (notshown).

FIG. 18B and 18C are finite element analysis deflected shape predictionsfor an example mode of vibration of sensor element assembly 1800 andshow the vibration deflected shape motion 1822. Sensor element assembly1800 may be a direct replacement for sensor element assembly 200 and mayfunction in the same way as previously described.

Additional Micro Electro Mechanical Sensors, MEMS, may be incorporatedinto the meter that provide complementary fluid process variablemeasurements, which may be used either individually and/or incombination with existing meter process fluid measurements. Resulting ineither all new process meter fluid outputs and/or compensations that mayimprove existing meter process fluid outputs. These MEMS transducers mayinclude but are not limited to pressure, pH, ultrasonic, acceleration,etc.

It is noted that the examples shown and described are provided forpurposes of illustration and are not intended to be limiting. Stillother examples are also contemplated.

1. A fluid parameter meter to measure at least one parameter of a fluid,comprising: an outer conduit; a sensor element assembly disposed in theouter conduit and having at least one straight uniform sensor elementwith an open interior to convey the fluid inside of the sensor elementassembly; at least one mounting flexure fixedly attached to the sensorelement assembly and to the outer conduit, the at least one mountingflexure configured to enable the sensor element assembly to vibrate in anatural radial mode shape of vibration; at least one vibration driver tocause the sensor element assembly to vibrate; and at least one vibrationsensor to sense the vibration of the sensor element assembly.
 2. Avibrating element type meter to measure at least one parameter of afluid, comprising: an outer conduit for conveying the fluid; a sensorelement assembly disposed in the outer conduit and comprised of at leastone substantially straight uniform sensor element having an interiorconfigured to convey the fluid inside of the sensor element assembly,and being separated from the outer conduit by a substantially uniformannular space configured to convey the fluid outside of the sensorelement assembly; one or more mounting flexures fixedly attached to theat least one sensor element and to the outer conduit, the one or moremounting flexures being configured so that the at least one sensorelement to vibrate in a natural radial mode shape of vibration; at leastone vibration driver to cause the sensor element assembly to vibrate; atleast one vibration sensor to sense the vibration of the sensor elementassembly; and control electronics cooperating with the vibration sensorand the vibration driver to controllably vibrate the sensor elementassembly in at least one prescribed mode of vibration, at a prescribedmagnitude; wherein the control electronics being operable to produce atleast one output signal from the control electronics proportionallyrelated to the at least one parameter of a fluid.
 3. The meter accordingto claim 2, wherein the one parameter of a fluid is selected from thegroup comprising at least one of: fluid density, Mass concentration,Volume concentration, Reynolds Number; fluid viscosity, absolute andkinematic; fluid flow rate; and fluid calculated result.
 4. The meteraccording to claim 2, wherein the vibration driver and the vibrationsensor each includes one of: a permanent magnet mounted in associationwith the sensor element assembly and an electrical coil mounted inassociation with the outer conduit; and an armature mounted inassociation with the sensor element assembly and an electrical coilmounted in association with the outer conduit.
 5. The meter according toclaim 2, further including a temperature sensor where the temperaturesensor provides a temperature related signal to the control electronicsproportionally related to the temperature of the sensor elementassembly.
 6. The meter according to claim 2, further comprising a wearguard associated with the sensor element assembly to protect the sensorelement assembly from damage.
 7. The meter according to claim 2, whereinthe sensor element further includes openings for the fluid to flowbetween the interior of the sensor element, and the annular space. 8.The meter according to claim 7, wherein the openings are shaped toinduce fluid to flow there through.
 9. The meter according to claim 2,wherein the sensor element assembly is comprised of one of: a pluralityof sensor elements arranged concentrically, and a plurality of sensorelements arranged in parallel.
 10. The meter according to claim 2,wherein the at least one prescribed mode of vibration inverts its shapeat least once along the length of the sensor element assembly.
 11. Avibrating element type sensor for a meter to measure at least oneparameter of a fluid, comprising: an outer conduit for conveying thefluid; a sensor element assembly disposed in the outer conduit andcomprised of at least one straight uniform sensor element having an openinterior configured to convey the fluid inside of the sensor elementassembly, and being separated from the outer conduit by a substantiallyuniform annular space configured to convey the fluid outside of thesensor element assembly; one of more mounting flexures fixedly attachedto the at least one sensor element and to the outer conduit , the one ormore mounting flexures being configured so that the at least one sensorelement to vibrate in a natural radial mode shape of vibration; at leastone vibration driver to cause the sensor element assembly to vibrate;and at least one vibration sensor to sense the vibration of the sensorelement assembly.
 12. The sensor according to claim 11, capable ofoperating in conjunction with controlling electronics, wherein the oneparameter of a fluid is selected from the group comprising fluiddensity, fluid viscosity, fluid flow rate, and fluid calculated result.13. The sensor according to claim 11, wherein the vibration driverincludes a permanent magnet mounted in association with the sensorelement assembly and an electrical coil mounted in association with theouter conduit.
 14. The sensor according to claim 11, further including atemperature sensor where the temperature sensor provides a temperaturerelated signal to control electronics proportionally related to thetemperature of the sensor element assembly.
 15. The sensor according toclaim 11, wherein the vibration sensor includes a permanent magnetmounted in association with the sensor element assembly and anelectrical coil mounted in association with the outer conduit.
 16. Thesensor according to claim 11, further comprising a wear guard associatedwith the sensor element assembly to protect the sensor element assemblyfrom damage.
 17. The sensor according to claim 11, wherein the sensorelement further includes openings for the fluid to flow between theinterior of the sensor element, and the annular space.
 18. The sensoraccording to claim 17, wherein the openings are shaped to induce fluidto flow there through.
 19. The sensor according to claim 11, wherein thesensor element assembly is comprised of one of: a plurality of sensorelements arranged concentrically, and a plurality of sensor elementsarranged in parallel.
 20. The sensor according to claim 11, wherein theat least one prescribed mode of vibration inverts its shape at leastonce along the length of the sensor element assembly.